Seat heater



Dec. 12, 1961 s 3,013,141

SEAT HEATER Filed Dec. 22, 1958 INVENTOR. LESLIE L. ELklS Ar'rogqayUnited States Patent 3,013,141 SEAT HEATER Leslie L. Ellis, 29650 RyanRoad, Warren, Mich. Filed Dec. 22, 1958, Ser. No. 782,151 1 Claim. (Cl.219-46) This invention relates to heating pads and more particularly toa low voltage electric resistance heating pad.

It is the object of the present invention to provide a very simplifiedlow voltage electric resistance heating pad which is particularlyadapted for mounting upon the seat and backrest of a vehicle, and havinglead wires terminating in a plug adapted for removable projection withinthe cigarette lighter receptacle. 7

It is another object to provide a simplified low voltage heating padconsisting of a felt strip with a continuous electric resistance wirecircuitously extending over one surface thereof and nested down into thebody of the strip defining a heating coil, together with means such asstitching or staples for securing the coil thereon.

It is another object to complete the heating pad by the applicationthereto of a covering envelope of suitable material, such as cotton,velveteen, wool or the like.

It is another object to provide a heating pad employing a plain electricresistance wire, which is circuitously laid down without coiling upon aresilient backing strip and secured thereto and wherein a low amperage,such as two to three amps, of current are utilized at a voltage of 6 to12. volts direct current.

These and other objects will be seen from the following specificationand claim in conjunction with the appended drawing in which:

FIG. 1 ,is a fragmentary schematic side elevational view of the presentheating pad mounted upon the seat and connected to a vehicle dashboard.

FIG. 2 is a plan view, on an enlarged scale, of the present electricheating pad, partially broken away for illustration.

FIG. 3 is a fragmentary section on an enlarged scale taken on line 3-3of FIG. 2.

FIG. 4 is a fragmentary section taken on line 4-4 of FIG. 2, on anenlarged scale.

FIG. 5 is a wiring diagram showing a use of a highlow switch for theheating pad.

"FIG. 6 is a side elevational view on an enlarged scale of one form ofplug for the lead wires of the heating pad.

FIG. 7 is a fragmentary plan view illustrating the use of staples forsecuring the wire upon the felt strip.

FIG. 8 is a fragmentary section taken on line 8-8 of FIG. 7.

It will be understood that the above drawing illustrates merely apreferred embodiment of the invention and that other embodiments arecontemplated within the scope of the claim hereafter set forth.

Referring to the drawing, the present heating pad shown in FIG. 2includes a pair of rectangularly shaped resilient strips of material11-12, preferably of felt. Parallel spaced straps 13 interconnectopposed spaced portions of the two strips and are secured thereto atpoints 14. These straps provide a hinge connection between said strips.

Individual heating coils 15-16 are mounted and secured respectively uponeach of the strips 11-12. Each heating coil consists of a continuouselectric resistance wire 17 circuitously mounted on and extending overthe surface of the respective strips on one side thereof and nested andprojected down into the body thereof. Accordingly, respective coils15-16 lie entirely within the plane of strips 11-12.

Suitable means are employed, such as the continuous stitching 18,anchored in said strips looped over and ice throughout the length of thewire 17 for immovably securing said wires to the respective strips.Alternately as shown in FIGS. 7-8, the said wire 17 may be immovablysecured in its embedded relation on strip 11 by a continuous series ofwire staples 42' which retainingly overlie the top surface of wire 17 asat 44, FIG. 8, and whose free ends are bent inwardly against and intothe bottom surface of the felt strip 11 as at 45.

Referring to FIG. 2, each of the coils 15-16 are substantially in theform of a double spiral with the respective ends of coil 15 terminatingin the contact points 19-25 upon strip 11. The insulated lead wires20-24 are respectively joined to contact points 19-25 and extend fromsaid strip through the electrical oil and on switch 21 with actuator 22,and terminate in the plug 23 with end contact button 42, as shown on anenlarged scale in FIG. 6.

The respective free ends of second coil 16 on resilient strip 12 extendtherefrom as at 17, FIG. 2, and are respectively joined to end portionsof coil 15, as at points 26-27 respectively, in a parallel circuitrelation.

Utilizing the present 12 volts direct current battery power sourceavailable in many vehicles today, the said coils 15-16 when plugged intothe cigarette lighter receptacle 40 of a vehicle dashboard 41, as shownin FIG. 1, will use approximately 1.88 amps. per coil at 12 volts DC. or.94 amp. per coil at 6-volts D.C., thus demonstrating the very low powerconsumption of the present heating pad.

The respective pads 11-12 in the spaced relation shown are enclosedwithin a suitable fabric envelope 28-29, and the assembly is completedwith the application thereto of the continuous beading 30 which isperipherally stitched at 31 along the edges of said envelope and securedto the respective adjacent edges of the strips 11-12.

Suitable goods or material are employed for this covering which wouldhave some body such as cotton, velveteen, wool, or upholsteringmaterial. Spaced pairs of eyelets 32 are secured through the respectiveends and intermediate portions of the assembled heating pad, providingmeans of securing said pad to seat 37 and backrest 35 of a vehicle seat,for example, employing fastening straps or tiedowns 36-38, FIG. 1.

Employing the heating pad in this fashion, the respective top and bottomportions 33 and 34 are arranged at approximately QO-degrees with respectto each other in view of the hinge connection 13, so as to cooperativelybear against said backrest and upon the seat.

The insulated lead wires generally indicated at 39, FIG. 1,corresponding to the individual lead wires 20-24, FIG. 2, terminate inthe removable plug 23 which is manually projected into the cigarettelighter aperture 40. There is a second yielding contact 43 for saidplug, FIG. 6 to establish suitable electrical connection to thelowvoltage D.C. power source, namely the vehicle storage battery.

FIG. 5 shows a slight variation of the electrical circuit shown in FIG.2 and wherein heating coils 15-16, diagrammatically indicated, areconnected to a conventional 12-volt DC. power source 46, and including amanually adjustable high-low switch for operating the heating coil ineither a series or parallel circuit with said power source.

Lead 20 from said power source joins coil 15, which through lead 24,terminates in contact 47 engaging the movable shorting plate 48 on themanually movable switch armature 51. In the position shown in FIG. 5,said shorting plate engages contact 49 on lead 17 to coil 16 with thecircuit back to the power source completed through lead wire 56 andnormally open switch 22, when closed.

This provides a series circuit between said coils with a voltage drop of6-volts over each coil so that each coil draws approximately 1 amp. Thisproduces a constant and steady heating temperature for the pad ofapproximately 80 degrees F.

Armature 51 carries a pair of spaced contacts 4952 respectivelyconnected with lead '53 to coil 16 and lead 54 back to power source 46.By manually shifting the armature 51 to the left from the position shownin FIG. 5, there is established a parallel circuit with a 12-volt dropover each of the coils 15-16.

The current flow would be through lead 20, coil 15, lead 24, contacts 47and 52, and leads 53 and 50 back to power source 46. The circuit throughthe other coil is through lead 54, contacts 52 and 49, coil 16 and lead50 back to the power source. Thiscorresponds to a higher heat whereineach coil draws approximately 2-amps. at 12-volts and produces aconstant heating temperature of approximately 110 degrees F.

Off and on switch 21-22 from either of the circuits, FIGS. 2 and may beeliminated, if desired, with energization of the heating padaccomplished merely by introduction of plug 23 within cigarette lighteraperture 40 within the conventional vehicle dashboard 41 such as shownin FIG. 1. r While the illustrative preferred embodiment shows apreferred use for vehicles, it is contemplated that the present heatingpad may be employed in any other environment desiring a low andinexpensive heat, as for example, an electric blanket or similar heatingpad or for, use in chairs or couches.

It has been found that the present heating pad preferably operates ondirect current electrical energy. However, it would be possible toutilize alternating current or employ a suitable rectifier therewith.

Having described my invention, reference should now be had to thefollowing claim:

In an electric heating pad, a pair of spaced felt strips, a continuouselectric resistance wire circuitously mounted on one side of andextending over the surface of each of said strips, respectively andnested down into the general plane of said strips, defining anindividual heating coil for each strip, stitching on each strip loopedover and securing said wires to said strips respectively, a pair ofspaced straps interconnecting adjacent spaced portions of said strips, afabric envelope enclosing said strips, insulated lead wires connected toand extending from the respective ends of one coil, and adapted forconnection to a power source, and an electrical circuit including ahigh-low switch having a two-position longitudinally reciprocalarmature, a shorting plate on said armature for connecting said coils inseries with said power source when in one position for low heating, andspaced insulated contacts on said armature adapted to connect said coilsin a parallel circuit with said power source for higher heating whenlongitudinally moved to a second position.

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